I have my left tail-light disassembled because I'm looking for a problem with the left turn signal.

While cleaning 3 or 4 decade's crud off the tail lamp bulbs, I ran across something a little out of the ordinary.

My left tail light bulb is something I've not seen before, and I'm wondering if it is one of the original factory-installed bulbs.

First, the metal part of the bulb is white metal, not brass like you'd expect.

Second, the inscription reads: PHILLIPS 1073 12/16V 32CP[] Holland.

Hmmm...not a 1156 or 1157 like the others...

Comments?

I'm going to upgrade to at least halogen, or maybe LED bulbs for the increased safety and visibility.

Steve

Bg;

Many manuf. use brass, Phillips uses nickel plated...no diff...and if you cross the numbers, it's still an 1156/7!

Use anti-corrosive paste* to keep either type from growing greenstuff!

Halogens lamps are OK, but do not up the taillight lamp wattage the increased heat will melt lenses....also brake light switch will not survive...LEDS MAY be an improvement, but its NOT guaranteed! Do tests!

* http://www.intelab.com/swem/anti_corrosive_paste.htm

Jim;

I you had used two of the brass base bulbs from the same manufacturer, I bet a hot fudge sundae the lamp-out indicator would have been satisfied too and stayed OFF!

Lamp-out indicators work by balancing magnetic fields produced by right and left side currents against each other to cancel. When new, lamps are guaranteed from the same manuf. and even batch, replacing a lamp later with one which is not from the same manufacturer as the other means there may be a slight, but significant diff in the right and left side currents...and the magnetic sensors are sensitive enough to pick this up and trigger the warning light. On vehicles, with Lamp out sensors, lamps should be replaced in pairs to avoid this...

You are entitled to you opinion, but I personally don't see a noticeble difference in quality between nickel plated and brass based lamps...but corrosion will occur on both and stop them both from working!

Cheers

All the original Volvo OEM bulbs had a silver base. Much higher quality IMO.
The 1073 is a European version of our 1156 and/or 1157 bulb.

When Volvo started using the bulb failure system on 240's a lot of people would replace a silver base bulb with a generic yellow base bulb and the bulb warning light would stay on. The resistance was different on the yellow base bulbs so you had to use the silver base bulb to get the light to go out.

Jim, 66 122s

After cleaning the contacts and the bulb, my left turn signal works fine now.

The odd bulb has its glass a little loose from the base, so it will be replaced this afternoon.

Still can't quite visualize what was causing the problem; apparently the bulb lost contact during the time I was working on the front turn signal. Was driving me nuts for a while!

Transient currents or current reversals can do weird arcing, especially at (exclusively at?) these mechanical connections that may be a tad loose after a few (hah! 40+) years.

You want to know something really odd? My wife's Chebbie Cavalier (wagon) has the typical side-post battery connections. About once a year (usually when it's cold) one of us will go out and get a normal start-up sequence but get the dreaded "CLUNK" followed by absolutely no power whatsoever.
Turns out, the connector comes ever so loose due to vibration and it arcs under the heavy starter load. Instant oxidation of current path and no more juice...
A "quick" dismount/mount of the terminals (always the "hot") and all is well for another year.

LED bulbs...

Lots of fly-by-night copycats have jumped on the LED bandwagon now that consumer acceptance is on the rise. Beware.
LED light output is individually less than for incandescent so you need a fairly large "array" to get good results. Also be certain to use the correct color as putting a red LED behind an amber lens will kill the visible output.

Some manufacturers put all the LEDs in series and use a internal or separate transformer to boost the voltage to the unit. Most gang together several groups of series LEDs in parallel to get the desired output (LEDs are voltage sensitive and need 1.5v -I think, could be 3v- to work, therefore they are ganged in series to make 12v useful).

--
Mike!

Here's an interesting sidebar about LED's.

There is at least one type of LED that changes color based on the electrical input. I think ata +6V to 12V it goes green, between -6V and +6V it shows yellow (or orange) and at -6V to -12V it is red. A neat idea for replacing 'idiot lights!'

I installed Red LED bulbs in my Ford Police Interceptor tail lights but behind the red lenses, they were no more effective than the incandescent bulbs, so I took them out. If I can get some 1157 or 1156 bulbs that put out white light I'd probably try thema gain.

For better tail/stop/turn signals, I'd look into Halogen bulbs over incandescent ones.

I used one of those on a science project as a kid. The particular unit I used was red on "+" DC, green on "-" DC and yellow on AC.

The primary advantage of LED lighting is the very low current draw and very long bulb life... NOT brightness. Of course if you make the array big enough...

--
Mike!